diff --git a/src/libkomapnik.py b/src/libkomapnik.py
index 9275325..70a7c04 100644
--- a/src/libkomapnik.py
+++ b/src/libkomapnik.py
@@ -90,7 +90,7 @@ def xml_linesymbolizer(color="#000000", width="1", opacity="1", linecap="butt",
   if dashes:
     dashes = '<CssParameter name="stroke-dasharray">%s</CssParameter>'%(dashes)
   rasterizer = ""
-  if float(width) < 2:
+  if float(width) < 4 and not dashes:
     rasterizer = ' rasterizer="fast"'